1. Field of the Invention
The present invention relates to a ratchet transmission control mechanism for a ratcheting tool for driving fasteners.
2. Description of the Related Art
U.S. Pat. No. 5,573,093 to Lee issued on Nov. 12, 1996 discloses a ratchet transmission control mechanism of a screwdriver that includes a casing having a head at one end, toothed shaft inserted into an axial center hole on the head to hold a bit for turning screw, two stop blocks mounted in a respective slot on the head of the casing and retained in place by a clamp for engagement with the toothed portion o the toothed shaft, an adjusting cap mounted around the toothed shaft over the head of the casing and retained in place by a locating ring. When the adjusting cap is turned to the middle position, the two stop blocks are forced into engagement with the toothed portion of the shaft for permitting the shaft to be turned by the casing in both ways. When the adjusting cap is turned to the leftward position or the rightward position, only one stop block is forced into engagement with the toothed portion of the shaft, and the shaft can be turned by the casing in one direction.
It is, however, found that assembly procedure of such a ratchet transmission control mechanism is troublesome and time-consuming. In addition, each of the stop blocks is engaged with the toothed portion of the shaft by one tooth and thus has poor ratcheting effect.
The present invention is intended to provide an improved ratchet transmission control mechanism for a ratcheting tool that mitigates and/or obviate the above problems.